Question

Write about the elements of Xylem.

[Review question: Pg. No: 224]

Answer 1

Xylem Xylem is a conducting tissue which conducts water, mineral nutrients upward from root to leaves. Xylem gives mechanical support to the plant body. Xylem is composed of:
1. Xylem tracheids: These are elongated or tube-like dead cells with hard, thick and lignified walls. Their ends are tapering, blunt or chisel-like and devoid of protoplast. They have large lumen without any content. Their function is conduction of water and providing mechanical support to the plant.
2. Xylem fibres:
These cells are elongated, lignified and pointed at both the ends. Xylem fibres provide mechanical support to the plant.
3. Xylem vessels:
These are long cylindrical, tube like structures with lignified walls and wide central lumen. These cells are dead as these do not have protoplast. They are arranged in longitudinal series in which the partitioned walls (transverse walls) are perforated, and so the entire structure looks-like a water pipe. Their main function is to transport of water and also to provide mechanical strength.
4. Xylem parenchyma:
These are living and thin walled cells. The main function of xylem parenchyma is to store starch and fatty substances